Prime Minister Theresa May denied reports Friday morning that the U.K. had increased its financial offer to the European Union as part of its steps to leave the bloc.

"What I've made clear to my EU counterparts in relation to financial contribution is what I set out in my Florence speech, which is that I've said nobody need be concerned for the current budget plan that they would have to pay more or receive less as a result of the U.K. leaving and that we will honor the commitments we have made during our membership," Prime Minister Theresa May told reporters in Brussels Friday morning.

Back in September, May said publicly for the first time that the U.K. would honor all of its financial commitments before leaving the EU. This is one of the most sensitive issues in the Brexit negotiations given that the remaining 27 EU countries do not want to contribute more or receive less money from the EU budget as a result of the U.K.'s departure.

Despite the public words, the U.K. hasn't until now outlined a proposal for calculating the amount that it has promised to the EU throughout its membership. The EU wants a proposal on the table and a deal on this issue before proceeding with talks on their future trading relationship.

"Now there needs to be detailed work on this… We are going through them line by line, will continue to go through them line by line," May told reporters about the U.K.'s proposal for a financial settlement.

The European Commission has said that that amount could be between 60 to 100 billion euros (between $71 billion and $118 billion).

The aim in Brexit negotiations at the moment is to move forward on the payments issue, citizens' rights and the Irish border by mid-December. Without an agreement on these three areas by then, the timeline for Brexit talks becomes complicated, increasing the possibility of a "hard Brexit" — meaning there could be higher tariffs for businesses on both sides of the English Channel.

The 27 countries have nonetheless given a green light at a summit in Brussels Friday to their technical teams so they can start preparing the next phase of negotiations. Though they are not sure that by mid-December there will be "sufficient progress" on the three key areas, they want to be ready to kick off trade talks as soon as possible.

Dalia Grybauskaitė, the Lithuanian president, said at her arrival in Brussels on Friday morning that Brexit needs to move "from words to real deeds."

"It's time to go for real negotiations and not just negotiating in the media by rhetoric," she said.

Leo Varadkar, the Irish prime minister, welcomed May's vision to not establish a physical border in Ireland but recognized that there are details missing in this area.

"There are obviously still delays on the three issues… but I think… We are making some progress," he said.